Chromium-free passivation for Salzgitter Flachstahl's hot-dip galvanized products

Chemical passivation is a conversion layer that temporarily protects galvanized steel against corrosion. While passivation containing chromium (III) was initially the state of the art for hot-dip galvanized steel, including StronSal^® products, this has now been completely replaced by a completely chromium-free passivation. From September to December last year, the three hot-dip galvanizing lines were successively converted to the new passivation, so that only chromium-free passivated material has been produced since the beginning of this year. This changeover was preceded by extensive investigations by Salzgitter Mannesmann Forschung, several operating trials on the plants and numerous tests at our customers, which were positively evaluated and thus ultimately led to the approval and introduction of the new passivation.

The advantages of this chromium-free passivation are obvious. It is free of both heavy metals and nitrates and therefore makes a contribution to environmental protection and sustainability. In laboratory tests, it also showed a better corrosion protection effect than the previous chromium (III)-containing passivation. All other important factors for our customers, such as tribological properties, paint adhesion, bonding suitability and weldability, are at a comparable level to the previously used product.

Further information can be found in our data sheet Chromium-free Passivation.

Our technical customer support will be happy to answer your questions about chemical passivation and other topics.